Filter for smoking
A filter for smoking includes a filter medium, and a means for heating the filter medium or a periphery of the filter medium.
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This is a Continuation Application of PCT Application No. PCT/JP03/10877, filed Aug. 27, 2003, which was published under PCT Article 21(2) in Japanese.
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2002-258988, filed Sep. 4, 2002, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a filter for smoking.
2. Description of the Related Art
For removing the harmful substances from tobacco smoke, it has been proposed to add various adsorbents and modifiers to filters for cigarettes.
However, since the components having a high boiling point, e.g., benzo[a]pyrene, exhibits behavior equal to that of particles, it was difficult to remove selectively the components having a high boiling point by using the conventional tobacco filter.
Japanese Patent Disclosure No. 60-110333, for example, discloses a tobacco filter made of acetate fiber carrying granular blue-green alga Spirulina. It is reported in this prior art that a tobacco smoke was passed through a pipe provided with a filter carrying the blue-green alga Spirulina so as to determine the adsorption removal rate relative to the filter that did not carry the blue-green alga Spirulina. The removal rates are 42.4% for nicotine, 53.2% for tar, and 75.1% for 3,4-benzopyrene.
On the other hand, Japanese Patent Disclosure No. 62-79766 proposes a tobacco filter prepared by rolling a sheet carrier carrying floc of Fomes annosus/Ganoderma lucidum mixture or powder/floc of Coriolus versicolor. It is reported that the removal rate of 3,4-benzopyrene was 62% and 35% for the respective filters.
However, the conventional tobacco filters exemplified above are incapable of sufficiently removing the high boiling point components from the tobacco smoke.
BRIEF SUMMARY OF THE INVENTIONAccording to an embodiment of the present invention, there is provided a filter for smoking, comprising a filter medium, and a means for heating the filter medium or a periphery of the filter medium.
The means for heating the periphery of the filter medium used in the present invention is not for directly heating the filter medium but includes, for example, a smoking article (cigarette holder) for indirectly heating from the outside the filter medium wrapped with a chip paper.
In the smoking filter of the present invention, it is desirable for the filter medium to be formed of heat resistant fibers. It is desirable for the filter formed of heat resistant fibers to exhibit thermal stability such that the filter is not modified even when heated to about 300° C.
In the smoking filter of the present invention, it is desirable for the filter medium to be a high efficiency filter capable of removing substantially 100% of particles. The term “high efficiency filter” means a filter capable of removing substantially 100% of particle components contained in the tobacco smoke and capable of delivering vapor components substantially completely. It is possible for the fiber diameter and the ventilation resistance of the high efficiency filter to be substantially equal to those of the ordinary filter medium. To be more specific, the high efficiency filter preferably has a fiber diameter of sub-microns to scores of microns and the ventilation resistance not higher than 200 mmH2O.
Also, it should be noted that, since the present invention is characterized in that filtration is performed so as to change gas-liquid distribution of the smoke through heating, it is possible to expect the same effect even when heated smoke is passed through a filter medium that is not heated. Such being the situation, it is possible to heat the smoke before it passes through the filter medium so as to change the gas-liquid distribution, followed by passing the smoke through the filter medium. To be more specific, it is possible to arrange the high efficiency filter immediately rearward of a combustion cone. For example, since a smoke-generating portion does not move in the case of an aerosol cigarette such as AIRS (registered trade mark), it suffices to arrange the high efficiency filter immediately rearward of the smoke-generating portion. Also, if the high efficiency filter is used in combination with a low ignition wrapper, it is possible to arrange the filter medium by making a tobacco section sufficiently short because the natural combustion rate is low.
It is desirable for the heating means used in the smoking filter of the present invention to be capable of controlling the temperature of the filter medium within a range of between 100° C. and 200° C. The filter temperature may be regulated in a two-stage manner such as 200° C. and 100° C. The smoking filter of the present invention may further comprise a cooling section. Still further, it is possible for the smoking filter of the present invention to be used in combination with charcoal, layered phosphate and other additives.
According to the present invention, applying such heat that permits evaporating necessary components, which contribute tobacco aroma and/or taste, and does not evaporate the high boiling point components can selectively filter the components having a high boiling point.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Examples of the present invention will now be described with reference to the accompanying drawings.
Automatic smoking experiments were conducted by using equipment constructed as shown in
In other words, it is possible to selectively penetrate necessary components, which contribute to tobacco aroma and/or taste, having a boiling point lower than that of nicotine by heating the filter medium so as to filter non-volatile components in tar.
Incidentally, in the experiments reported above, the filter temperature was controlled constant throughout the first puff to the sixth puff. However, it is considered reasonable that the similar effect can be obtained even if the filter is kept heated to a prescribed temperature, e.g., 125° C., for only a short time in each puff.
Next, a construction in which the untipped cigarette 10 was mounted to the smoking filter 1 as shown in
Where a charcoal filter was not arranged in the front of the high efficiency filter medium, a tendency that the component having the higher vapor pressure exhibited the higher penetration was observed. On the other hand, where a charcoal filter was arranged in the front of the high efficiency filter medium, it be found possible to selectively filter the components having a high vapor pressure in spite of the fact that the penetration of nicotine was substantially equal to that for the former case. In other words, it has been found possible to control the components in both particle phase and vapor phase in the case where the smoking article provided with the heating means defined in the present invention is used in combination with an adsorbent/additive represented by charcoal.
Next, zirconium phosphate 4 (available from Daiichi Kigenso Kagakukogyo Co., LTD., CPZ-100), which is a layered phosphate, was sandwiched between two HEPA filters 2. Then, automatic smoking experiments were conducted by using equipment of the construction shown in
The description given above covers the case where a high efficiency filter medium (HEPA filter), which permits removing substantially 100% of the particle components in the tobacco smoke and also permits penetrating the vapor components substantially completely, is heated. However, it is conceivable to remove about 50% of the undesired component such as benzo[a]pyrene and aromatic amines, while penetrating almost all components, which contribute to tobacco aroma and/or taste, having a boiling point lower than that of nicotine.
Claims
1. A filter for smoking, comprising:
- a filter medium; and
- a means for heating the filter medium or a periphery of the filter medium.
2. The filter for smoking according to claim 1, wherein the filter medium is formed of heat resistant fibers.
3. The filter for smoking according to claim 1, wherein the filter medium is a high efficiency filter capable of removing substantially 100% of particles.
4. The filter for smoking according to claim 1, wherein the heating means is capable of controlling the temperature within a range of between 100° C. and 200° C.
5. The filter for smoking according to claim 1, wherein the heating means is capable of controlling the temperature within a range of between 100° C. and 200° C. in two or more stage.
6. The filter for smoking according to claim 1, wherein further comprising a cooling section.
7. The filter for smoking according to claim 1, wherein further comprising a charcoal filter.
8. The filter for smoking according to claim 1, wherein the filter medium contains a layered phosphate as an adsorbent.
Type: Application
Filed: Mar 3, 2005
Publication Date: Jul 7, 2005
Patent Grant number: 8826916
Applicant:
Inventors: Michihiro Inagaki (Tokyo), Takashi Hasegawa (Tokyo), Kazunori Sugai (Tokyo)
Application Number: 11/070,192